Blown-In Insulation Calculator Pro (USA)
Calculate Bags, Depth & R-Value for Attics & Walls (2024 Standards)
*Estimates include 10% overage factor for settling and waste. Actual coverage may vary based on machine settings and installation technique.
How to Use This Insulation Calculator
Measuring for blown-in insulation is easier than you think. Simply enter the Length and Width of your attic space, or enter the total square footage directly. Select your preferred material (Cellulose is popular for DIY due to better air blocking, while Fiberglass is lighter). Adjust the R-Value slider based on your local building code.
Understanding R-Value & Depth
The R-Value measures thermal resistance. Higher numbers mean better insulation. Different materials achieve different R-Values per inch:
- Cellulose: Approx. R-3.2 to R-3.8 per inch.
- Fiberglass: Approx. R-2.2 to R-2.7 per inch.
- Mineral Wool: Approx. R-3.0 to R-3.3 per inch.
Our tool automatically calculates the depth in inches required to reach your target R-Value and updates the visual diagram so you can visualize the coverage.
Why You Need 10% More Bags
This calculator automatically adds a 10% waste factor. Blown-in insulation settles over time (especially cellulose), and some material is always left in the hopper or hose. Ordering extra ensures you don’t run out mid-project, which could compromise your thermal barrier.
